Module qgroup 

Quota group (qgroup) management: hierarchical accounting of disk usage

Qgroups track how much disk space a subvolume (or a group of subvolumes) uses. Every subvolume automatically gets a level-0 qgroup whose ID matches the subvolume ID. Higher-level qgroups can be created and linked into a parent–child hierarchy so that space usage rolls up through the tree.

Quota must be enabled on the filesystem (see crate::quota) before any qgroup operations will succeed. Most operations require CAP_SYS_ADMIN.

Structs

QgroupInfo

Usage and limit information for a single qgroup.

QgroupLimitFlags

Which limit fields are actively enforced on a qgroup.

QgroupList

Result of qgroup_list: overall quota status and per-qgroup details.

QgroupStatusFlags

Status flags for the quota tree as a whole (BTRFS_QGROUP_STATUS_KEY).

Functions

qgroup_assign

Assign qgroup src as a member of qgroup dst (i.e. src becomes a child of dst).

qgroup_clear_stale

Destroy all “stale” level-0 qgroups — those whose corresponding subvolume no longer exists.

qgroup_create

Create a new qgroup with the given qgroupid on the filesystem referred to by fd.

qgroup_destroy

Destroy the qgroup with the given qgroupid on the filesystem referred to by fd.

qgroup_limit

Set usage limits on a qgroup.

qgroup_list

List all qgroups and overall quota status for the filesystem referred to by fd.

qgroup_remove

Remove the child–parent relationship between qgroups src and dst.

qgroupid_level

Extract the hierarchy level from a packed qgroup ID.

qgroupid_subvolid

Extract the subvolume ID component from a packed qgroup ID.